Look, just because you think somebody is trolling, you don't have to be complete jerks about it. What if the guy's seriously confused about how navigation works? That's the biggest problem with GameFaqs, not the trolls, the jerks who accuse everybody of trolling.
If you don't have a map... dig down to bedrock. You will be standing on Y=2. Build blocks in a stair pattern up to map max height. Place signs on each step incrementing by 1 from the bottom as you ascend. You can reference this system any time you need to know your Y coordinate.
problem there Terra. Minecraft's Y axis is actually the Z axis ...
Because F*** cartesian coordinates THATS WHY!
Hmmm... that's a good point.
Ah well, it's better than my original idea of taking a screenshot, circling (and rather poorly, too... we're talking about doing this in MSPaint) the "Y" coordinate on a map, and writing (again, rather poorly): "Here it is!".